Murakami Tomonori, Natsuka Shunji, Nakakita Shin-Ichi, Hase Sumihiro
Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.
Glycoconj J. 2007 Jul;24(4-5):195-206. doi: 10.1007/s10719-006-9026-8. Epub 2007 Mar 14.
To clarify the structure of non-sialic acid anionic residue on N-glycans in the mammalian tissues, we have isolated sialidase-resistant anionic residue on N-glycans from bovine lung. Analyses by partial acid hydrolysis and glycosidase digestions combined with a two-dimensional HPLC mapping method revealed that the major sialidase-resistant anionic N-glycan had a fucosylbianntenary core structure. The anionic residue was identified as a sulfate ester by methanolysis, anion-exchange chromatography, and mass spectrometry. The linkage position of the sulfate ester was the 6-position of the GlcNAc residue on the Manalpha1-6 branch. This conclusion was based on the results of glycosidase digestions followed by two-dimensional HPLC mapping. Furthermore, the disialylated form of this sulfated glycan was dominant, and no asialo form was detected. The structure of the major anionic N-glycan prepared from bovine lung and having a sulfate was proposed to be the pyridylamino derivative of Siaalpha2-3Galphalbeta1-4(HSO(3)-6)GlcNAcbeta1-2Manalpha1-6(Siaalpha2-3Galbeta1-4GlcNAcbeta1-2Manalpha1-3)Manbeta1-4GlcNAcbeta1-4(Fucalpha1-6)GlcNAc.
为阐明哺乳动物组织中N-聚糖上非唾液酸阴离子残基的结构，我们从牛肺中分离出了对唾液酸酶具有抗性的N-聚糖阴离子残基。通过部分酸水解和糖苷酶消化结合二维高效液相色谱图谱分析方法表明，主要的对唾液酸酶具有抗性的阴离子N-聚糖具有岩藻糖基双天线核心结构。通过甲醇解、阴离子交换色谱和质谱分析确定该阴离子残基为硫酸酯。硫酸酯的连接位置是Manα1-6分支上GlcNAc残基的6位。这一结论基于糖苷酶消化后二维高效液相色谱图谱分析的结果。此外，这种硫酸化聚糖的双唾液酸化形式占主导，未检测到去唾液酸形式。从牛肺中制备的具有硫酸盐的主要阴离子N-聚糖的结构被认为是Siaα2-3Galβ1-4（HSO(3)-6）GlcNAcβ1-2Manα1-6（Siaα2-3Galβ1-4GlcNAcβ1-2Manα1-3）Manβ1-4GlcNAcβ1-4（Fucα1-6）GlcNAc的吡啶氨基衍生物。
